Vaso-occlusive device delivery system

Abstract

A vaso-occlusive device delivery assembly includes a pusher assembly and a vaso-occlusive device detachably coupled to the pusher assembly by an attachment member is frictionally secured within a lumen of the pusher assembly. A heat generating member is disposed in the pusher assembly lumen, along with a pressure generating material, such that, when heat is generated by the heat generative device, the pressure generating material increases a pressure in the pusher assembly lumen, thereby dislodging the attachment member from the pusher assembly and detaching the vaso-occlusive device from the pusher assembly.

What is claimed is: 
     
       1. A vaso-occlusive device delivery assembly, comprising:
 a pusher assembly including a substantially fluid tight pressure chamber in a distal end portion thereof; 
 a thermally activated pressure generating material disposed in the pressure chamber; 
 a heat generating member at least partially disposed in the pressure chamber, the heat generating member substantially surrounded by the pressure generating material; and 
 a vaso-occlusive device detachably coupled to the pusher assembly distal of the pressure chamber, wherein the pressure generating material comprises a solid that is configured for changing state into, or otherwise releasing at least one of, a liquid or a gas that increases a pressure in the pressure chamber, thereby detaching the vaso-occlusive device from the pusher assembly, in direct response to heat generated by the heat generating member, wherein 
 the vaso-occlusive device comprises an attachment member at a proximal end thereof, the attachment member being frictionally secured to the pusher assembly, wherein a proximal end of the attachment member comprises a distal wall of the pressure chamber, such that the increased pressure in the pressure chamber expels the attachment member from the pusher assembly. 
 
     
     
       2. The vaso-occlusive device delivery assembly of  claim 1 , the pusher assembly further comprising a resilient retaining member frictionally secured to the attachment member, wherein the increased pressure deforms the resilient retaining member. 
     
     
       3. The vaso-occlusive device delivery assembly of  claim 2 , wherein the resilient retaining member is made of a deformable polymer. 
     
     
       4. A vaso-occlusive device delivery assembly, comprising:
 a pusher assembly; 
 a tubular connecting member at a distal end of the pusher assembly, the tubular connecting member at least partially defining a substantially fluid tight pressure chamber; 
 a thermally activated pressure generating material disposed in the pressure chamber; 
 a heat generating member at least partially disposed in the pressure chamber; and 
 a vaso-occlusive device detachably coupled to the pusher assembly, a proximal end of the vaso-occlusive device attached to a distal end of the tubular connecting member, wherein a phase change in the pressure generating material, when heated by the heat generating member, occurs that increases a pressure in the pressure chamber, thereby directly causing detachment of the vaso-occlusive device from the pusher assembly. 
 
     
     
       5. The vaso-occlusive device delivery assembly of  claim 4 , wherein the pressure generating material is located adjacent to, or in contact with, the heat generating member. 
     
     
       6. The vaso-occlusive device delivery assembly of  claim 4 , wherein the pressure generating material comprises a solid. 
     
     
       7. The vaso-occlusive device delivery assembly of  claim 6 , wherein the pressure generating material comprises an inorganic salt hydrate selected from the group consisting of sodium carbonate monohydrate, calcium sulfate dihydrate, calcium sulfate pentahydrate, copper sulfate pentahydrate, and sodium bicarbonate. 
     
     
       8. The vaso-occlusive device delivery assembly of  claim 4 , wherein the heat generating member is a resistive heating coil. 
     
     
       9. The vaso-occlusive device delivery assembly of  claim 4 , the vaso-occlusive device comprising an attachment member at a proximal end thereof, the attachment member being frictionally secured to the pusher assembly, wherein a proximal end of the attachment member comprises a distal wall of the pressure chamber, such that the increased pressure in the pressure chamber expels the attachment member from the pusher assembly. 
     
     
       10. The vaso-occlusive device delivery assembly of  claim 9 , the pusher assembly further comprising a resilient retaining member frictionally secured to the attachment member, wherein the increased pressure deforms the resilient retaining member. 
     
     
       11. The vaso-occlusive device delivery assembly of  claim 10 , wherein the resilient retaining member is made of a deformable polymer. 
     
     
       12. The vaso-occlusive device delivery assembly of  claim 4 , wherein the tubular connecting member comprises a detach zone, such that the increased pressure ruptures the tubular connecting member in the detach zone, and wherein the detach zone is thermally or mechanically weakened. 
     
     
       13. The vaso-occlusive device delivery assembly of  claim 4 , wherein the heat generated by the heat generating member raises the temperature of the pressure generating material, such that the phase change in the pressure changing material occurs. 
     
     
       14. A vaso-occlusive device delivery assembly, comprising:
 a pusher assembly; 
 a tubular connecting member at a distal end of the pusher assembly, the tubular connecting member at least partially defining a substantially fluid tight pressure chamber; 
 a thermally activated pressure generating material disposed in the pressure chamber; 
 a heat generating member at least partially disposed in the pressure chamber; and 
 a vaso-occlusive device detachably coupled to the pusher assembly via the tubular connecting member, wherein the pressure generating material, when heated by the heat generating member, increases a pressure in the pressure chamber, thereby rupturing the tubular connecting member and detaching the vaso-occlusive device from the pusher assembly. 
 
     
     
       15. The vaso-occlusive device delivery assembly of  claim 14 , wherein the pressure generating material is a single substance that changes state into, or otherwise releases at least one of, a liquid or a gas in response to heat generated by the heat generating member. 
     
     
       16. The vaso-occlusive device delivery assembly of  claim 14 , wherein the tubular connecting member comprises a detach zone, such that the increased pressure ruptures the tubular connecting member in the detach zone, and wherein the detach zone is thermally or mechanically weakened.